Rslogix 500 Training - Online Edits
In this lesson we are going to start learning how to make online edits to the PLC. So far, you have downloaded programs to the PLC that requires the PLC be put into program mode. In real world terms, means that the machine is stopped. This isn't always possible.
To begin, open up your program from the end of the RsLogix 500 - Latches OTL and OTU lesson, download it if necessary, and go online.
1. Make sure your processor is in REMOTE RUN mode and highlight rung 0 so it is red.
2 Press the delete key on your keyboard. THIS IS IMPORTANT! It really is that easy to delete a rung in a program. While it isn't deleted yet, it has been marked in the processor to be deleted during the next test of edits. You have two indicators that this has happened:
- One seemingly obvious indicators is the DDDDDDs on the left side of the rung.
- Capital letters in the area circled in red to the left of the rung means these edits are in the PLC processor.
Here is the trick to the capital DDDDDDs that makes them not so obvious. You saw how easily you could accidentally hit the delete key and mark a rung for deletion. You can now go offline and come back to this PLC another day and that rung is still marked for deletion. Or someone else with a different computer could accidentally mark a rung for deletion somewhere deep inside the program and you make an edit somewhere else. When you test your edits it will include deleting this rung. There is a much more subtle indicator you should always check when going online with a PLC and that is right below the "REMOTE RUN" indicator. If you look at the image above before our edit you will see it says "No Edits". Now it says "Edits Exist".
Another note to start observing during edits is the green bars on the left and right of the rung. This means that these rungs can be scanned by the PLC. I didn't say they are being scanned by the PLC. This will be an IMPORTANT distinction in later lessons.
2. Click the down arrow to the right of "Edits Exist". From here you can either cancel your edits or test your edits. Click Test Edits.
3. Now it says "Edits Active" below the REMOTE RUN. The green bars to the left and right of the rung are gone and our green DDDDDDs are now blue. This means that this rung is still in the PLC but cannot be scanned. Remember, capital letters where the DDDDDs are means that it is in the processor.
4. Click the arrow to the right of the "Edits Active". You can either Assemble Edits or Untest Edits. Untesting edits takes you back to step 2 where the rung is marked for deletion but is still active in the program. Click Assemble Edits.
5. Assembling the edits makes them permanent. In this case the PLC has permanently removed the rung from the PLC program.
6. Highlight the new rung 0 and press the delete key on your keyboard. Same as last time, your rung 0 now has capital DDDDDs meaning it is marked for deletion in the processor but the green to the left and right of the rungs tell you it is still active in the program. DO NOT click the test edits button link you did last time.
7. Scroll down to rung 3 and make sure it looks the same as rung 3 below. Depending on your screen resolution you won't see the rung marked for deletion above. While it would be easy to spot being rung 0 of our 4 rung program, imagine if it were hundreds of rungs long. This is why looking for that "Edits Exist" indicator is so important.
8. Highlight it so that it is RED but this time hit the enter key on your keyboard. You have started rung edits on this rung. Now we have two rungs in place of the one but they are both identical. The lowercase eeeeeeeee rung is the one you can edit on and only exist on your computer. The lowercase rrrrrrrr rung is the rung that will be replaced but nothing about these edits have gone to the PLC yet.
9. Highlight the address of the OTE instruction in the editable rung and press ENTER so it's address can be changed.
10. Change it to O:0.0/3 and press ENTER. A few of you are concerned now because that is the same address we used in rung 0 and 1, Hold that until the next lesson and concentrate on the online editing principles.
11. Note that even though we have made changes to the eeeeeee rung, the rrrrrrrrr rung is the same as it was and it is what is in the PLC program.
12. Now you have made your edits and maybe you are questioning if you checked to see whether edits existed or what edits you have made to the PLC. You can find them, however it isn't as obvious as it should be. Go to Search then Find... from the top menu or press the Control key and F simultaneously on your keyboard.
13. Near the bottom of the Find dialog you will see "Rung Zones" and if you select "Any IRD Zone" it will find all of these edits. You can use the Find Next button to increment through them or the Find All button to get a list of them.
14. Scroll back up to rung 0 and make sure you can see both the DDDDDDs in rung 0 and the eeeeeeees in rung 3. Note the capital vs lowercase and the green vs blue.
15. Highlight rung 3 and click the "Accept Current Rung Edits" checkbox circled below.
16. Rung 3's eeeeeeeees are now IIIIIIIIIIs. Rung 4's rrrrrrrrrr are now RRRRRRRRs. This means that they have been inserted into the PLC. But rung 3 is still blue and rung 4 is still green so rung 4 is active.
17. Scroll back up so you can see rung 0 and rung 3 then click the "Test Edits" button circled below.
18. The rung 0 DDDDDDs went blue which means they are no longer active in the PLC but they are still there. Remember, capital letters in these edits mean they are in the PLC.
19. The rung 3 IIIIIIIIs are now green and the rung 4 RRRRRRRs are now blue. In summary we are testing rung 0 being deleted and rung 3 which turns on the blue light instead of the yellow light. Don't worry about what the buttons and lights do at this point. Stay focused on understanding these online editing steps.
20. The blue icon to the right of the circled icon below can be used to untest these edits which will take it back to step 16. Practice several times if needed then when you are ready click the "Assemble Edits" button circled below.
21. The Assemble edits button makes the rungs that were green in the test edits stage of step 19 permanent and deletes the rungs that were blue in step 19 which included rung 0 marked for deletion and rung 4 which was the old version of rung 3 which replaced it.
It is VERY IMPORTANT that you understand this lesson. When you get out in the field, there will be many occasions that you will have to do online editing. Making sure you know what happens on what step of the editing process and how to find existing edits in the program will make things go smoother.
Is the blue light being addressed by all these outputs still bothering you? Proceed to the RsLogix 500 - Program Flow, Does the Last Rung Win lesson where we will discuss this further.
Go to the Allen Bradley RsLogix 500 PLC Training PLC Training Getting Started Lesson series to select your next lesson. There are also many other Lesson Series on PLC Programming and Industrial Automation.